Hot add/remove of network adapters and enabling device naming in Windows Server Hyper-V

One of the cool new features in Window Server vNext Hyper-V (in Technical Preview at the moment of writing) is that you gain the ability to hot add and remove NICs.  That might sound not to important to the non initiated in the fine art of virtualization & clouds. But it is. You see anything you can do to a VM configuration wise that does not require downtime is good. That’s what helps shift the needle of high availability to that holey grail of continuous availability.

On top of that the names of the network adapters are now exposed to the guest. Which is also great. It’s become lot easier to automate the VM network configuration.

Hot adding NICs can be done via the GUI and PoSh.

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But naming the network adapter seems a PowerShell only game for now (nothing hard, no sweat). This can be done during creation of the network adapter. Here I add a NIC to VM RAGNAR connected to the ISCSI-GUEST switch & named ISCSI.

Add-VMNetworkAdapter –VMName RAGNAR –SwitchName ISCSI-GUEST –Name ISCSI

Now I want this name to be reflected into the VM’s NCI configuration properties. This is done by enabling device naming. You can do this via the GUI or PoSh.

Set-VMNetworkAdapter –VMName RAGNAR –Name ISCSI –Devicenaming On

That’s it.

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So now let’s play with our existing network adapter “Network Adapter” which connects our Hyper-V guests to the LAN via the HYPER-V-GUESTS switch? Can you rename it?  Yes, you can. In PoSh run this:

Rename-VMNetworkAdapter –VMName RAGNAR –Name “Network Adapter” –NewName “LAN”

And that’s it. If you refresh the setting of your VM or reopen it you’ll see the name change.

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The one thing that I see in the Tech Preview is that I need to reboot the VM to see the Name change reflected inside the VM in the NIC configuration under advance properties, called “Hyper-V Network Adapter Name”. Existing one show their old name and new one are empty until then.

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Two important characteristics to note about enabling device naming

You notice that one can edit this field in NIC configuration of the VM but it doesn’t move up the stack into the settings of the VM. Security wise this seems logical to me and it’s not intended to work. It’s a GUI limitation that the field cannot be disabled for editing but no one can try and  be “funny” by renaming the ethernet adapter in the VMs settings via the guest Winking smile

Do note that this is not exactly the same a Consistent Device Naming in Windows 2012 or later. It’s not reflected in the name of the NIC in the GUI, these are still Ethernet, Ethernet 2, … Enable device naming is mainly meant to enable identifying the adapter assigned to the VM inside the VM, mainly for automation. You can name the NIC in the Guest whatever works best for you and you’ll never lose the correlations between the Network adapter in your VM settings and the Hyper-V Network Adapter name in the NIC configuration properties. In that respect is a bit more solid/permanent even if some one found it funny to rename all vNICs to random names you’re still OK with this feature.

That’s it off, you go! Download the Technical Preview bits from MSDN, start exploring and learning. Knowledge is seldom a bad thing Winking smile

April 24th–Windows 2003 Is 10 Years Old

I’d like to chime in on a recent blog post by Aidan Finn Hey Look–Your Business Is Running On A 10-Year Old Server Operating System (W2003). The sad thing is this is so true and “the good” thing is some are even still on Windows Server 2000 so even in worse shape. Now I realize that not all industries are the same but keeping your operating systems up to date does have it’s benefits for all types of companies.

  • Security Improvements
  • Improved, richer, enhanced features
  • New functionality
  • Support for state of the art hardware & software
  • Supported for that day the SHTF
  • Future Proofing of your current investments

For one, all the above  it will save you time and money. On top of that mitigates the risks of lost revenue due to security incidents & unsupported environments no one can fix for you.

Think about it, if you’re running Windows Server 2000 or 2003 chances are you are paying for software to provide functionality that’s available right out of the box. You’re also putting in the extra effort & jumping through loops to run those on modern server grade hardware.

You’re also building up debt. Instead of yearly improvements keeping your infrastructure & services top notch you’re actively digging an ever bigger, very expensive, complex and high risk hole where you’ll have to dig your self out off. If you can, that is. Not a good place to be in. Still think leveraging software assurance is a bad thing?

So while way to many companies now have to assigned resources to mitigating that looming problem we’re focusing on other ventures (such as Hyper-V, Azure, Hybrid Cloud, …) and just keep our OS up to date at a steady pace, like before. Well people that doesn’t happen by accident. We’ve maintained a very healthy pace of upgrading to the most recent version of windows in our environments and at times I have had to fight for that and I’m I will again..But look at our base line, even if the economy tanks completely we’re in darn good shape to weather that storm and come out ahead. But it’s not going to happen by sitting there avoiding change out of fear or laziness. So start today.A point where I agree with Aidan completely: if your “Zombie ISV” and other vendors are telling you Windows 2003 is great and you shouldn’t use those new unproven versions of the OS; they are really touting BS. They have fallen behind so far on the technology stack that they need you to stay in their black hole of despair with them or they’ll go broke. Just move one. Trust me, they need you more than the other way around

Some SAN Storage Fun

At the end of this day I was doing some basic IO tests on some LUNs on one of the new Compellent SANs. It’s amazing what 10 SSDs can achieve … We can still beat them in  certain scenarios but it takes 15 times more disks. But that’s not what this blog is about. This is about goofing off after 20:00 following another long day in another very long week, it’s about kicking the tires of Windows and the SAN now that we can.

For fun I created a 300TB LUN on a DELL Compellent, thin provisioned off cause, I only have 250 TB Smile

I then mounted it to a Windows 2008 R2 test server.

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The documented limit of a Volume in Windows 2008 R2 is 256TB when you use 64K allocation size. So I tested this limit by trying to format the entire LUN and create a 300TB simple volume. I brought it online, initialized it to an GPT disk, created a simple volume with an allocation unit size of 64K and well that failed with following error:

Failed Format300TB

There is nothing unexpected about this. This has to do with the maximum NTFS volume size supported on a GPT disk. It depends on the cluster size that is selected at the time of formatting. NTFS is currently limited to 2^32-1 allocation units. This yields a 256TB volume, using 64k clusters. However, this has only been tested to 16TB, or 17,592,186,040,320 bytes, using 4K cluster size. You can read up on this in Frequently asked questions about the GUID Partitioning Table disk architecture. The table below shows the NTFS limits based on cluster size.

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This was the first time I had the opportunity to test these limits I formatted part of that LUN to a size close to the limit and than formatted the remainder to a second simple volume.

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I still need get a Windows Server 2012 test server hooked up to the SAN. To see if anything has changed there. One thing is for sure, you could put at least 3 64TB VHDX files on a single volume in Windows. Not too shabby Smile. It’s more than enough to put just about any backup software into problems. Be warned, MSFT tested and guarantees performance & behavior up to 64TB in Windows Server 2012, but beyond that you’d better do your own due diligence.

The next thing I’ll do when I have a Windows Server 2012 host hooked up is, is create 64TB VHDX file and see if I can go beyond it before things break. Why, well because I can and I want to take the new SAN and Windows 2012 for a ride to see what boundaries we can push. The SANs are just being set up so now is the time to do some testing.